I worked for Princess many years ago as a musician backing shows and playing for dancing.
There are many things to consider. The hours are long and the pay isn't much. But most of your necessities are included so if you are frugal you can send almost all you pay home. But it's hard if you are married (I was, and had two children) or in a relationship because the contracts are long--three, six, and even nine months. And it can get very routine; in most positions you never get a day off.
But you see a lot of interesting places and meet a lot of interesting people--especially if you have a position where you come in contact with the passengers. I had never been on a ship before, and took the job almost on a whim. But it was the beginning of life-long love affair with the sea and with ships. I would very much recommend it so long as you are aware of the less desirable aspects and think you can accept them.